Juniper JNCIP-SP: Advanced Routing, MPLS, and Multicast Concepts

What determines which OSPF route is preferred when both are intra-area routes?

The OSPF metric.

Which OSPF external route is normally preferred: E1 with total cost 120 or E2 with cost 50?

E2 because 50 is lower than 120.

What is the conclusion if a router has no Area 0 interface in OSPF?

The design violates the normal OSPF backbone requirement.

What must be identical for OSPF neighbors to form an adjacency?

Hello and dead intervals.

What issue should be investigated first if an OSPF adjacency is stuck in EXSTART?

Interface MTU mismatch.

Which router becomes the DR in a segment with R1 priority 100, R2 priority 200, and R3 priority 0?

R2.

What is the most appropriate policy structure to export only the route 10.20.0.0/16 into an external protocol?

Match the prefix and accept it; reject other routes.

Which address type is important for checking OSPFv3 neighbor communication?

IPv6 link-local.

What does disabling Level 1 in IS-IS configuration imply?

Level 2 operation remains enabled.

What does the DIS in a broadcast LAN primarily provide?

A pseudonode representation of the LAN.

What feature allows selected Level 1 routes to become available to Level 2 routers in IS-IS?

Route leaking.

Which IS-IS path is preferred if Path A has a metric of 20 and Path B has a metric of 80?

Path A.

What is preferred in IS-IS metrics?

Lower IS-IS metric

What are three reasonable first checks for IS-IS adjacency troubleshooting?

Interface configuration, IS-IS level compatibility, Authentication

Which statement is correct about IS-IS and OSPF?

IS-IS is carried directly over the data-link layer.

Which path is preferred based on LOCAL_PREF in BGP?

Path A with LOCAL_PREF = 200

What is the purpose of the BGP policy that sets local preference to 250 for CUSTOMER community?

Increase preference for routes carrying the CUSTOMER community.

What should be investigated first if a BGP session remains in Active?

TCP connectivity to the peer, BGP neighbor address/reachability

Why is multihop configured in EBGP?

The peer is not necessarily directly connected.

What is the primary problem if a BGP route is not installed due to next hop resolution?

Next-hop reachability

What is R1 allowed to do as an IBGP route reflector?

Reflect the route to R3.

Which feature allows multiple eligible BGP paths to be installed?

Multipath

What are legitimate uses of BGP communities?

Identifying customer routes, Applying routing policy, Controlling route treatment

Which route is preferred based on MED in BGP?

Route 1 with MED = 50

What Junos CoS function performs initial mapping for DSCP classification?

Classification

What feature limits traffic entering an interface to 100 Mbps?

Policer

Which feature controls bandwidth allocation among queues?

Scheduler

Which mechanisms are relevant to packet treatment during congestion?

Packet loss priority, Drop profile

What mechanism modifies outgoing QoS markings in CoS?

Rewrite rule

What happens when a multicast packet arrives on ge-0/0/1 but the unicast routing table says the best path back to the source is through ge-0/0/0?

Packet fails RPF.

What model is used when a receiver wants traffic specifically from source 192.0.2.50 for multicast group 232.1.1.1?

Source-Specific Multicast (SSM).

Which two components should be checked first if a host cannot receive an IPv4 multicast stream?

IGMP membership and multicast routing/RPF state.

What role can the RP play in traditional ASM PIM-SM?

Meeting point for multicast sources and receivers.

What is the major goal of two RPs using the same logical RP address?

RP redundancy and distribution.

Which statement best describes PIM-DM?

It initially floods traffic and prunes unwanted branches.

What does the outer label in a provider MPLS core identify in an L3VPN?

The transport path toward the egress PE.

What causes VRF-B to import routes exported with RT 65000:100?

RT matching.

Which two components are fundamental to distributing VPN routes between PE routers?

MP-BGP and VPN route attributes such as RTs.

What is the purpose of the VRF table?

Isolate customer routing information.

Which feature allows an MPLS VPN path to be treated as an OSPF intra-area path?

Sham link.

What mechanism can help prevent a routing loop for a multihomed customer site?

Site of Origin.

What is likely the problem if a PE has a valid VPNv4 route but cannot forward traffic?

Transport underlay.

What design concept is appropriate for a customer VRF needing controlled access to the public Internet?

Provide a controlled route-leaking/shared Internet routing design.

Which control-plane technology is required for IPv6 VPN route distribution?

MP-BGP.

What service is most appropriate for two customer Ethernet interfaces needing a point-to-point Layer 2 service across an MPLS core?

L2 circuit.

Which technology is appropriate for three customer sites needing to participate in the same multipoint Ethernet VPN?

VPLS.

What does traditional VPLS normally do when it receives a frame?

Learn the source MAC against the incoming interface/service.

Which protocol is central to EVPN control-plane MAC/IP route distribution?

MP-BGP

What are three important capabilities of EVPN?

BGP-based MAC/IP reachability, Multihoming, Ethernet-segment/DF-related mechanisms.

What EVPN functionality should be investigated if traffic is being duplicated or forwarded incorrectly?

Designated Forwarder behavior.

What should be investigated if traffic fails between CE1 and CE2 in a Layer 3 VPN?

MPLS transport/LSP connectivity between PE1 and PE2.

What does a working VPN control plane not guarantee?

A working MPLS data plane.

What is the purpose of the MPLS transport LSP?

To ensure connectivity between provider edge routers.

What is the role of IGMP in multicast networking?

To manage host membership in multicast groups.

What does the term 'Designated Forwarder' refer to in EVPN?

The mechanism that determines which PE forwards traffic toward a multihomed Ethernet segment.

What is the function of MP-BGP in EVPN?

To distribute Ethernet reachability information.

What should be checked first when a VPN does not work?

Is the CE route in the correct VRF?

What does the acronym L2 stand for in networking?

Layer 2

What does the acronym L3 stand for in networking?

Layer 3

What is the significance of the VPN service label?

It is used for MPLS forwarding in VPNs.

What is the role of BGP in a VPN?

To advertise routes and manage path selection.

What does OSPF stand for?

Open Shortest Path First

What is the purpose of the OSPF DR election?

To determine the designated router in a multi-access network.

What does the term 'route reflection' refer to in BGP?

A method to reduce the number of BGP connections in a network.

What is the function of the MED attribute in BGP?

To signal the preferred path to neighboring AS.

What does the acronym RPF stand for in multicast routing?

Reverse Path Forwarding

What is the purpose of a policer in networking?

To rate limit traffic.

What does the term 'multihoming' refer to in networking?

Connecting a device to multiple networks for redundancy.

What is the significance of the 'show route' command?

To display routing information in a network device.

What does the term 'BGP community' refer to?

A way to group routes for policy application.